AstraZeneca, Corporate Taxes, Tiger Woods: Your Wednesday Evening Briefing

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Good evening. Here’s the latest.

1. Another setback for AstraZeneca.

Britain said that it would offer alternatives to AstraZeneca’s Covid-19 vaccine for adults under 30 after European regulators described a “possible link” between the vaccine and rare blood clots. Above, the AstraZeneca vaccine being administered in Milan last month.

The government’s announcement came after months of backing AstraZeneca’s shot — a heavy blow for the world’s most widely used vaccine and to the more than 100 countries relying on it, particularly in the global south. Europe’s medical regulator stopped short of advising that use of the vaccine be curbed in the bloc.

U.K. and European regulators said blood clots were occurring at a rate of about one in 100,000 vaccines administered. European officials reiterated that the benefits of the vaccine outweighed the risk, but urged health professionals and recipients of the shot to be cautious about symptoms.

2. And in the U.S., a worrisome projection is now a reality: Most infections in the country are now caused by a contagious virus variant that was first identified in Britain.

Dr. Rochelle Walensky, the director of the Centers for Disease Control and Prevention, also said that 52 of the agency’s 64 jurisdictions were now reporting cases of B.1.1.7.

Federal health officials are tracking reports of increasing cases associated with day care centers and youth sports, and hospitals are admitting younger adults with “severe disease,” Dr. Walensky said.

That variant has been found to be most prevalent in Michigan, Florida, Colorado, California, above in February, Minnesota and Massachusetts, as scientists warn of a possible fourth virus surge. New cases, hospitalizations and deaths have declined from their peaks in January, but new infections have increased after plateauing.

3. The Biden administration detailed corporate tax increases that would raise $2.5 trillion over 15 years for infrastructure spending.

The plan, if enacted by Congress, would raise the corporate tax rate to 28 percent from 21 percent, and limit the ability of American companies to evade taxes by shifting profits overseas. The plan would also replace fossil fuel subsidies with tax incentives that promote clean energy production. Here’s a breakdown of the proposal.

President Biden said he was willing to compromise on the $2.3 trillion infrastructure bill but would not tolerate “doing nothing.” Much of the overhaul is aimed at reversing a deep slide in corporate taxes signed into law by President Donald Trump.

5. Kentucky just became the only red state to expand voting rights in the wake of the 2020 election.

Republican lawmakers and the state’s Democratic governor, Andy Beshear, backed a new law that, among other provisions, establishes three days of early voting and introduces voting centers that would allow for more in-person balloting options.

Kentucky Republicans bucked their party’s trend for both political and logistical reasons: Under sweeping new pandemic election rules, Republicans had one of their best cycles in years. And Kentucky already had a low bar to clear: Before 2020, it had some of the strictest voting laws in the country.

6. Two years after the Islamic State’s self-declared caliphate suffered stinging defeats in Syria and Iraq, the terrorist group has found a new lifeline in Africa.

Analysts say the group has forged alliances with local militant groups, many of which are only loosely connected to the Islamic State. But as violence from Islamist extremists on the African continent reached a record high over the past year, the terrorist group has claimed victories in an effort to inspire supporters.

Most recently, the Islamic State claimed credit last week for a dayslong rampage in northern Mozambique, where militants with distant ties to the terrorist group ambushed Pemba, a key port town, pictured above. Dozens were killed.

7. Tiger Woods was driving nearly 90 miles per hour in a 45-m.p.h. zone when he crashed his car in February, according to the Los Angeles County sheriff.

Woods was driving his S.U.V. along a tricky stretch of road in Los Angeles County. By the time his car struck a tree, it was traveling at an estimated 75 m.p.h.

The golfer was not citied for driving too fast and no criminal charges will be filed, the sheriff said. There were no signs of impairment or intoxication, and Woods — who has no memory of the collision — was wearing his seatbelt.

8. Evidence is mounting that a tiny subatomic particle is being influenced by unknown forms of matter and energy, according to new research that could rewrite the laws of physics as we thought we knew them.

Muons, which are like electrons but far heavier, were subjected to an intense magnetic field in experiments performed at the Fermi National Accelerator Laboratory, in Batavia, Ill., above. That caused them to wobble like spinning tops in a manner inexplicably inconsistent with the theory known as the Standard Model.

The findings, scientists say, could eventually lead to a breakthrough in our understanding of the universe more dramatic than the heralded discovery in 2012 of the Higgs boson, a particle that imbues other particles with mass.

9. Sourdough bread. Vegetable regrowing. Panic shopping. And now — backyard maple sugaring.

Tapping maple trees and boiling the sap into syrup — known as sugaring — isn’t a new hobby, but the D.I.Y. quarantine trend soared in backyards this year. There has been a run on at-home evaporators and other syrup-making accouterments, and a surge in subscriptions to maple syrup websites. “Making a pure natural product just feels good,” said one longtime sugarer.

The maple sugar season will be over by the end of April, but that leaves time to take up another backyard hobby: mushroom identification. Those scary-looking mushrooms in your yard are actually a good sign, our garden columnist explains.

10. And finally, maybe we were born to be lazy.

Scientists have found that grizzly bears, like people, are prone to choose the path of least resistance, favoring flat paths over slopes and gentle speeds over sprints. By comparing bears in the wild with captive bears on a treadmill being baited with hot dogs and apples, researchers concluded that wild grizzlies, like us, have an innate urge to avoid exertion.

The scientists had expected the wild bears to move at the most metabolically efficient speed, but in reality their average pace traveling through Yellowstone National Park was far lower: a lackadaisical 1.4 miles per hour. The study is the latest in a growing body of research that suggests that certain animals — including humans — are hard-wired to avoid strenuous activity.